Fixed grammatical error in ceph-guide.rst
Fixed grammatical error in ceph-guide.rst

Made changes in section Managing Ceph to correct the grammatical mistake.

Signed-off-by: Richa Yadav <ricyadav@cisco.com>

Change-Id: I2ed13f766dd39a7ac816af86664986b8d2700d80

GalenMa/kolla,openstack/kolla,toby82/kolla,openstack/kolla,nihilifer/kolla,mandre/kolla,coolsvap/kolla,coolsvap/kolla,mrangana/kolla,negronjl/kolla,stackforge/kolla,toby82/kolla,nihilifer/kolla,stackforge/kolla,rahulunair/kolla,intel-onp/kolla,tonyli71/kolla,mrangana/kolla,coolsvap/kolla,intel-onp/kolla,GalenMa/kolla,stackforge/kolla,mandre/kolla,dardelean/kolla-ansible,dardelean/kolla-ansible,rahulunair/kolla,mandre/kolla,negronjl/kolla,tonyli71/kolla,toby82/kolla,negronjl/kolla,dardelean/kolla-ansible